On the WGSC Property in Some Classes of Groups

The property of quasi-simple filtration (or qsf) for groups has been introduced in literature more than 10 years ago by S. Brick. This is equivalent, for groups, to the weak geometric simple connectivity (or wgsc). The main interest of these notions is that there is still not known whether all finitely presented groups are wgsc (qsf) or not. The present note deals with the wgsc property for solvable groups and generalized FC-groups. Moreover, a relation between the almost-convexity condition and the Tucker property, which is related to the wgsc property, has been considered for 3-manifold groups.     

The scale dependence of lattice condensates

We show how to extract the condensates of composite operators, defined with respect to some scale μ, from explicitly μ-independent Monte Carlo results, using the renormalization group. For each composite operator, the object which is most naturally extracted from Monte Carlo is a renormalization group invariant quantity; in the case of the quadratic gluon operator, this quantity coincides with the trace anomaly.     

Mikrobestimmung des Bors in den Weinen der Aeolischen Inseln (Sizilien)

Zusammenfassung Nach kurzer Beschreibung einer neu vorgeschlagenen Mikromethode der Borsäurebestimmung werden die mit dieser Methode erhaltenen Analysenergebnisse von einigen echten Weinen der Aeolischen Inseln (Sizilien) mitgeteilt. Die gefundenen Werte bestätigen die Voraussicht und bekräftigen die Zuverlässigkeit der vorgeschlagenen Methode.Die zur Untersuchung gelangten 15 Weinmuster hat uns liebenswürdigerweise Herr Prof. G. Labruto von der Universität Messina zur Verfügung gestellt. Wir sagen hierfür unseren besten Dank.     

Investigation of the Thermal Stability of Laser Nitrided Iron and Stainless Steel by Annealing Treatments

Laser nitriding has revealed to be a very promising and effective treatment to improve the technical properties, like surface hardness and corrosion-wear resistance, of iron and steels. The high nitrogen concentration, the fastness and precision of the treatment and the easy experimental setup make this technique very suitable for applications on industrial scale. Samples of pure iron and austenitic stainless steel have been irradiated with ns laser pulses in the UV radiation range and analyzed by means of Conversion Electron Mössbauer Spectroscopy (CEMS), Resonant Nuclear Reaction Analysis (RNRA), Grazing Incidence X-Ray Diffraction (GXRD) and Microhardness. Mössbauer Spectroscopy, in particular, is capable of detecting the phase composition of the nitrided layer and therefore represents an essential tool for these kind of analysis. The thermal stability of the treated samples have been investigated by subsequent annealings at increasing temperatures in vacuum and in air. For iron samples the annealing treatment at 250°C shows a rather drastic phase transformation from phase (fcc) into (Fe₄N) while a strong depletion of N has been observed for 400°C or higher, regardless of the ambient pressure (atmospheric or vacuum). On the other hand, the stainless steel shows a very good thermal stability up to 500°C, but higher temperatures induce a gradual decrease in the nitrogen concentration which seems to be a common feature for both pure iron and stainless steel. Furthermore, annealing in air leads to the formation of a thin oxide layer on the surface of the iron sample which is easily characterized by Mössbauer spectroscopy.     

Desulphurative approaches to penem antibiotics. V. 2-(Functionalized methyl)penems from 3-methylenecepham-1-oxides

3-Methylenecepham-1-oxides are converted into 3-(functionalized methyl)-2-thiacephems, direct precursors of a group of valuable penem antibiotics.     

Ring nitrogen functionalization of 2-aminothiazol-4-acetic acid derivatives. I. Synthesis and properties of novel 2-aminothiazole N-oxides

Cyclization of thiocyanomethylketone oximes with hydroxylamine hydrochloride and oxidation of 2-aminothiazole derivatives with peracids are shown to afford the same products, which can be formulated either as 2-imino-3-hydroxy-2,3-dihydrothiazolines or 2-aminothiazole N-oxides. Compounds of this type bearing at position 4 an acetic or α-oxyiminoacetic residue are useful synthons for highly active β-lactam antibiotics; the problems connected with their preparation in a suitably protected form are examined. Scope and limitations of this previously unreported oxidation of the thiazole nucleus are discussed. All the products show limited stability in alkaline media: the 4-acetic derivatives, in addition, undergo a transposition to afford 4-methylidenethiazolidines. Possible types of isomerism and tautomerism are discussed in the light of the acquired spectral data. The uv and ir spectra of the compounds synthesized lend support to their formulation as 2-aminothiazole N-oxides.     

Il criterio dell'energia per un sistema elettromagnetico dissipativo

Riassunto Per un mezzo elettromagnetico immerso in un ambiente a temperatura costante, elettromagneticamente e termicamente passivo, si studia la legge di evoluzione della energia, determinando una funzione di Liapunov per il sistema, costituita dall'integrale dell'energia su una sfera che si contrae con velocità finita, più un termine superficiale che rappresenta il calore che fluisce attraverso la sfera.

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Summary We study the energy behavior for an electromagnetic material immersed in an environment, that is thermally and mechanically passive, at constant temperature. We determinate a Liapunov function, that is the energy integral on a sphere shrinking with a finite speed, plus a surface term corresponding to the heat flowing across the sphere.

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Lavoro eseguito nell'ambito del G.N.F.M. del C.N.R.     

A news procedure for experimental analysis of the post-buckling behaviour of structures by models

Summary By means of an examination of the common procedures for the analysis by models of the post-buckling behaviour of structures (in particular, framed) it is shown how these may not always be suitable, above all if we wish to extend the scanty field so far explored. On the other hand, to reach a final analytical formulation of this subject, experimental knowledge must definitely be improved.The proposed new experimental procedure aims at the solution of these problems and, in particular, at precision and reliability of measurements in the field of unstable branches.The first applications of our equipment seem to confirm that such aims have been reached.

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Sommario Attraverso un esame delle comuni metodologie di indagine, mediante modelli, del comportamento postcritico delle strutture (intelaiate, in particolare), viene mostrato come queste non sempre possono risultare idonee allo scopo, soprattutto se si volesse ampliare il limitato campo d'osservazione sin'ora esplorato. D'altro canto, per giungere ad una definitiva messa a punto della formulazione analitica dell'argomento occorre migliorare decisamente le conoscenze sperimentali al riguardo.La nuova metodologia sperimentale proposta è volta alla soluzione di tali problemi, riguardanti, in particolare, la precisione e la sicurezza di misura nel campo dei rami instabili.Le prime appliczaioni eseguite con l'apparecchiatura da noi messa a punto sembrano confermare come tali obiettivi siano stati raggiunti.

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Work carried out under grant of the C.N.R.